CBS Corp.'s "The Big Bang Theory" and "NCIS" are among the most-watched shows on television, with upward of 20 million viewers each. But in Nielsen's new ranking of programs with the greatest reach on Twitter, they aren't even in the top 10.

ENLARGE

The Nielsen data, which will be published for the first time Monday, provides new details on the number of tweets about TV shows and the size of the audience that sees them. It highlights that the programs that generate the most Twitter activity often aren't the ones with the highest viewership.

New data released Monday shows that the most watched TV shows are not heavily tweeted. Marketers have to understand that disconnect as they determine how Twitter plays into their ad-buying strategy. Amol Sharma reports. Photo: Getty Images.

For TV networks and advertisers looking to exploit the buzz about TV shows on Twitter, the data are a reminder that the social-media service's user base has a very different makeup than the mass-market TV-viewing audience that marketers spend tens of billions of dollars each year to reach. Twitter's 49.2 million U.S. users generally skew younger and are disproportionately in cities, for example, according to marketers and media analysts.

Still, marketers see potential value in knowing which shows have Twitter enthusiasts. For some, it is becoming a factor when they purchase TV time: The theory is that if fans are engaged on Twitter that "means the ads are also being paid attention to," said Steve Kalb, director of video investment at Mullen, an advertising firm owned by Interpublic GroupIPG0.38% of Cos. Mr. Kalb said the approach is still in the "experimental" phase.

Related

The stakes are high for Twitter, which is under the spotlight of an initial public offering of stock and has identified TV-related ad spending as a crucial revenue driver. The company has joined with several TV networks through its Amplify program, in which short video clips are distributed on Twitter with ads embedded. Another service allows marketers to target Twitter users who have seen one of their ads on TV.

"If your show is creating conversations on Twitter, it is more valuable, and you should get credit for that," said Rachael Horwitz, a spokeswoman for Twitter, which provided information to Nielsen to help create the new Twitter TV ratings. In its IPO filing, Twitter said its revenue doubled in the year's first six months to $254 million, compared with a year earlier. The company isn't profitable.

Some shows are hits both on social media and in the TV ratings. The much-anticipated finale of the AMC drama "Breaking Bad" was No. 1 in the Twitter TV ratings for the week of Sept. 23, with 9.3 million unique users seeing tweets about the show, and had the sixth-highest TV rating in the key demographic of 18- to 49-year-old viewers, according to Nielsen.

Interactives: Inside Twitter's IPO

Facebook Inc.,FB-1.26% which also is trying to carve out a role in the TV world, has said it will distribute a weekly report to major broadcasters showing the chatter and activity on the social network that is related to their TV shows.

Some programs—live events and competition shows such as NBC's "The Voice"—simply lend themselves to social-media activity, industry analysts say.

But many shows with mass-market appeal don't have as much traction on Twitter. CBS had five of the top 10 shows on TV during the week of Sept. 23, including the hit situation-comedy "Big Bang Theory" and "The Crazy Ones," a new comedy starring Robin Williams. None of those was in the top 10 of the Twitter TV ratings.

At an industry event in Beverly Hills this summer, CBS Chief Research Officer David Poltrack said "word of mouth" interactions about TV mostly still occur face to face, not on social media. He said that while Twitter's importance is growing and CBS is "immersing" itself in it, "right now it is focused on a small segment of the population."

CBS last month agreed to participate in Twitter's Amplify program. "We continue to work with all of the leading social networks to extend the fan experience of our shows," the company said in a written statement Friday.

Nielsen says the number of people tweeting about TV was 19 million in the second quarter, up 24% over the year-earlier period. Some TV executives have begun including Twitter statistics in pitches to advertisers. But for many on Madison Avenue, it is still unclear how much Twitter buzz should factor into their ad-buying strategy.

There is "still so much more research that has to be done to understand the value of it," said Ari Bluman, chief digital investment officer of GroupM, a media-buying arm of advertising firm WPPWPPGY0.66% PLC. "If a show is social does that mean it helps or hurts the advertisers? We are continuing to investigate," he said.

Many ad buyers say that despite Twitter's growing user base, the number of people tweeting about a particular show can be small. "Twitter's overall footprint is relatively small so that is problematic," said David Cohen, chief media officer at UM, a media-buying firm owned by Interpublic Group of Cos.

Aflac Inc. said it intends to test Twitter's TV ad products next year but hasn't made the leap yet. "We are a national company and our sales come from the suburban market more so than the metropolitan areas, where [Twitter's] strength lies," said Michael Zuna, chief marketing officer of the insurer.

"I have got a mass-market brand and our most important customers aren't in the major metro markets," he said.

This copy is for your personal, non-commercial use only. Distribution and use of this material are governed by our Subscriber Agreement and by copyright law. For non-personal use or to order multiple copies, please contact Dow Jones Reprints at 1-800-843-0008 or visit www.djreprints.com.